Fuel injection amount control system for diesel engine

Abstract

The present invention relates to a fuel injection amount control system for a diesel engine to control a fuel injection amount electrically by an electronic-hydraulic governor. In the invention, when a driver steps on the accelerator at 100% in acceleration to raise the engine speed suddenly and vigorously, a DC linear motor transfers a control rack to the full-rack position according to the engine speed to bring the necessary amount of fuel injection. The process is that the rack position detects the second rack position firstly and the control rack leaves the second rack position accordingly, then the DC linear motor suspends the control rack at the first rack position for a certain time under a signal, afterwards and the control rack is positioned to the full-rack position by another command given to the DC linear motor to operate again.

What is claimed is: 
     
       1. A fuel injection amount control system for a driver-controlled vehicle diesel engine to control a fuel injection amount of a fuel injection pump by a control unit for controlling an electronic-hydraulic governor based on the information signals from an acceleration sensor and an engine speed sensor, wherein; said electronic-hydraulic governor comprises: a DC linear motor operated by the signals from said control unit,   a control rack engaging with the plunger in the fuel injection pump body, the control rack being moveable in response to driver accelerator operation and to positions including a full-rack position,   a link transmitting the activation of the DC linear motor to the control rack,   a rack sensor detecting the position of the control rack; and   wherein said control unit stores the full-rack position according to the engine speed, calculates firstly the necessary amount of fuel injection based on the information signals detected by the acceleration sensor and the engine speed sensor and secondly a target rack position based on said fuel injection amount, and controls and position of the control rack by changing the value of electrical current to the DC linear motor in order to make the target rack position and real rack position coincide,     characterized in that the system operates so that when the control arm is advanced in acceleration in response to driver accelerator operation a first rack position is established lower than the full-rack position by a prescribed amount, and a second rack position is established further lower than said first rack position by a prescribed amount according to the engine speed respectively, and if the target rack position at 100% in acceleration is larger than the difference between the full-rack position and the second rack position, when the rack is initially positioned at less than the second rack position but moves to the second position, the control unit detects the second rack position and thereafter suspends the control rack at the first rack position for a prescribed time, whereby the control rack is prevented from overshooting by inertia.